<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .box{
            display: flex;

            width: 500px;
            height: 500px;
            border: 1px solid red;
        }

        .box1{
            /*order值越小，越靠前*/
            /*order: 0;*/
            /*flex item*/
            order: -2;
            width: 100px;
            height: 100px;
            background-color: #f00;
        }

        .box2{
            /*order: 0;*/
            order: -10;
            width: 100px;
            height: 100px;
            background-color: #0f0;
        }

        .box3{
            order: -1;
            width: 100px;
            height: 100px;
            background-color: #00f;
        }






    </style>
</head>
<body>
    <div class="box">
        <div class="box1"></div>
        <div class="box2"></div>
        <div class="box3"></div>
    </div>
</body>
<script type="text/javascript">

</script>

</html>
